beast cleaning and tidying:
* Consolidate small modules into one
* Remove Android-specific platform support
* Remove Chrono.h from beast_core.h
* Removed files:
  - TypeTraits.h
  - Utility.h
  - Net.h
  - Asio.h
* Remove zlib support:
  - Remove inline zlib library sources
  - Remove GZIPCompressorOutputStream
  - Remove GZIPDecompressorInputStream
* Remove obsolete or unused classes:
  - AbstractObject
  - BigInteger
  - BufferedInputStream
  - CacheLine
  - CPUMeter
  - DatagramSocket
  - DynamicObject
  - FileLogger
  - FPUFlags
  - Identifier
  - JSON
  - LocalisedStrings
  - MACAddress
  - MemoryAlignment
  - MemoryInputStream
  - MemoryMappedFile
  - NamedValueSet
  - OptionalScopedPointer
  - PerformanceCounter
  - PropertySet
  - ScopedTimeInterval
  - SparseSet
  - SpinDelay
  - StreamingSocket
  - StringPool
  - SubregionStream
  - Uuid
  - Variant
Add const_container
beast.streams improvements:
* New basic_std_ostream wraps any std::stream.
* New debug_ostream redirects output to debugger if attached.
New unit_test framework:
* Header-only!
* No external dependencies or other beast modules
* Compilation options allow for:
  - Stand-alone application to run a single test suite
  - Stand-alone application to run a set of test suites
  - Global suite of tests inline with the host application
  - Disable test suite generation completely
* Existing tests reworked to use the new classes
Implement beast::tagged_integer